diff --git a/crypto/hmac.go b/crypto/hmac.go
index a9afb1f..1cb7f6e 100644
--- a/crypto/hmac.go
+++ b/crypto/hmac.go
@@ -50,7 +50,8 @@
 		return ErrInvalidKey
 	}
 	hasher := hmac.New(m.Hash.New, keyBytes)
-	if hmac.Equal(signature, hasher.Sum(raw)) {
+	hasher.Write(raw)
+	if hmac.Equal(signature, hasher.Sum(nil)) {
 		return nil
 	}
 	return ErrSignatureInvalid
@@ -64,7 +65,8 @@
 		return nil, ErrInvalidKey
 	}
 	hasher := hmac.New(m.Hash.New, keyBytes)
-	return Signature(hasher.Sum(data)), nil
+	hasher.Write(data)
+	return Signature(hasher.Sum(nil)), nil
 }
 
 // Hasher implements the SigningMethod interface.
diff --git a/crypto/hmac_test.go b/crypto/hmac_test.go
index ff46861..129e293 100644
--- a/crypto/hmac_test.go
+++ b/crypto/hmac_test.go
@@ -1,10 +1,11 @@
 package crypto
 
 // import (
-// 	"github.com/dgrijalva/jwt-go"
 // 	"io/ioutil"
 // 	"strings"
 // 	"testing"
+
+// 	"github.com/SermoDigital/jose/jws"
 // )
 
 // var hmacTestData = []struct {
@@ -66,7 +67,7 @@
 // 	for _, data := range hmacTestData {
 // 		if data.valid {
 // 			parts := strings.Split(data.tokenString, ".")
-// 			method := jwt.GetSigningMethod(data.alg)
+// 			method := jws.GetSigningMethod(data.alg)
 // 			sig, err := method.Sign(strings.Join(parts[0:2], "."), hmacTestKey)
 // 			if err != nil {
 // 				t.Errorf("[%v] Error signing token: %v", data.name, err)
@@ -78,14 +79,14 @@
 // 	}
 // }
 
-// func BenchmarkHS256Signing(b *testing.B) {
-// 	benchmarkSigning(b, jwt.SigningMethodHS256, hmacTestKey)
-// }
+// // func BenchmarkHS256Signing(b *testing.B) {
+// // 	benchmarkSigning(b, jwt.SigningMethodHS256, hmacTestKey)
+// // }
 
-// func BenchmarkHS384Signing(b *testing.B) {
-// 	benchmarkSigning(b, jwt.SigningMethodHS384, hmacTestKey)
-// }
+// // func BenchmarkHS384Signing(b *testing.B) {
+// // 	benchmarkSigning(b, jwt.SigningMethodHS384, hmacTestKey)
+// // }
 
-// func BenchmarkHS512Signing(b *testing.B) {
-// 	benchmarkSigning(b, jwt.SigningMethodHS512, hmacTestKey)
-// }
+// // func BenchmarkHS512Signing(b *testing.B) {
+// // 	benchmarkSigning(b, jwt.SigningMethodHS512, hmacTestKey)
+// // }